SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f649439b03996b731edc5fa07822e3a03cbceac8f2e628bbcdccef7eed9f7417' 
  AND token = 'SsrnNKtk0u/InLs68IC8OFq+vDB094/IOBnPitX/DCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}